Magnet-meter.



R. J. EVEREST.

MAGNET METER.

APPLICATION FILED MAY 25, 1914.

Patented June 13, 1916.

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f n m UNITED STATES PATENT OFFICE.

RALPH 3'. EVEREST, OF LOS ANGELES, CALIFORNIA, ASSIGNOR TO ELECTRIC EQUIP- MENT COMPANY, OF LOS ANGELES, CALIFORNIA, A CORPORATION OF CALIFORNIA.

MAGNET-METER.

Specification of Letters Patent.

PatentedJune 13, 1916.

T 0 all whom it may concern:

Be it known that I, RALPH J. EVEREST, a citizen of the United States, residing at Los Angeles, California, have invented a new and useful Magnet-Meter, of which the following is a specification.

This invention comprises an instrument for measuring the attractive force of magnets in a convenient and accurate manner.

Heretofore it has been a common practice to test the strength of magnets by withdraw ing the armature from the magnet by means of a pair of spring scales. This method is injurious to the magnet by reason of the fact that the sudden withdrawal of the armature from the magnet causes a loss of from ten to twenty per cent. of the attractive force of the magnet.

The disadvantages of the above and other old methods of testing magnets are overcome by the present invention one Valuable use of which is to test the magnets in use as a part of the electrical equipment of hydrocarbon engines.

Referring to the accompanying drawings, which illustrate the invention, Figure 1 is a plan view of the appliance the convex portion of the casing being broken away. Fig. 2 is a side elevation, the face plate being removed. Fig. 3 is a transverse section on line se -00 of Fig. 2.

Referring in detail to the drawings, the semicircular casing 1 is provided with a base plate 2 to which is secured a pair of polepieces, one of said pole-pieces consisting of an outer base portion 3 and an inner deflected portion 5 and the other pole-piece consisting of an outer base portion 4 and inner deflected portion 6. The arms 5 and 6 of these pole-pieces are preferably formed at right angles to their base portions but this is not essential to the successful operation of the instrument. Said pole-pieces are secured to the base 1 by any suitable means, for example, the screws 3* and t. The base 1 is formed of brass or other non-magnetic material.

To the base 1 is secured a U-shaped standard 7 having upwardly extending arms 8 and 9. Between said arms 8 and 9 is pivotally supported the elongated armature 10 by means of the pintle 11 to which said armature is fixed. Sand standard 7 may be fastened to the base 1 by any suitable fastenmg means such as the screw 12,

15 designates a small spiral spring the front end of which is secured to the armature 10, the rear end of said spring being fastened to the standard 7 by means of a bent pin 16 soldered or otherwise secured to the upper end of the rear arm 9 of the standard 7. Said armature 10 carries an indicating hand 17 which moves over av graduated dial 18 best shown in Fig. 2, to indicate the amount of deflection of the armature 10 from the normal inclined position shown in full lines in Fig. 2. Said indicating hand 17 has an offset base portion 17 to bring the free end of the hand out beyond the dial 18. The outer portion of hand 18 always extends radially with respect to shaft or pintle 11.

In order to adjust the be ring of the pin tle 11, a cupped screw 19 and lock nut 21 are provided at the outer-end of said pintle. The face of the casing 1 is cut away opposite gheldial 18 and a glass 25 placed over said In Fig. 2 a magnet M is indicated in dotted lines in position to be tested.

In operation the poles of a magnet M to be tested are placed in contact with the base 1 and opposite the base members 3 and 4 of the pole-pieces, thus causing the magnetic flux to deflect the armature 10 more or less from the normal position shown in full lines in Fig. 2, according to the strength of the magnet being tested. The magnet will bring the armature more nearly to a horizontal position, the armature 10 and hand 17 moving in a clock-wise direction by reason of the upper end of the armature being normally maintained at a few degrees inclination toward the right hand pole-piece as shown in Fig. 2.

It will be seen that the spring 15 constitutes yielding means which offers increasing resistance to the movement of the armature in proportion to the strength of the magnet being tested.

It will be seen that the magnet being tested is not so placed as to form a complete magnetic circuit, owing to the non-magnetic material of the base plate 2 which separates the pole pieces 3 and 4 from the magnet M. Therefore the strength of the magnet is not lessened by the withdrawal of the instrument therefrom.

I claim:

An elongated armature, means to pivotally support said armature, a pair of pole-pieces having inner portions extending adjacent to the path of movement of the ends of said armature, said armature being mounted between said pole-pieces, said pole-pieces having outer portions adapted to be brought into proximity to the poles of the magnet to be tested, yielding means normally holding said armature in a position different from that which it tends to assume When the magnetic flux is passed therethrough, said yielding means offering increasing resistance to the movement of said armature by the magnetic flux, and means to indicate the amount of deflection of said armature from the normal position.

In testimony whereof I have hereunto signed my name in the presence of two subscribing witnesses at Los Angeles, in the county of Los Angeles and State of California, this 20th day of May, 1914.

RALPH J. EVEREST Witnesses:

ALBERT H. MERRILL, R. G. ROBERTS. 

